1. Field of the Invention
The present invention relates to stent deployment devices and methods for deploying stents. Embodiments of the invention relate to a system that provides for deploying a stent using an endoscope.
2. Description of the Related Art
Endoscopes are effective devices for diagnosing and treating patients with minimal intervention and discomfort and are often used to explore and perform biopsies in such areas as the alimentary tract. In general, an endoscope has a flexible elongated tubular body equipped with a miniature television camera or other viewing device, a light, and a working lumen or channel. The working channel is used to store and deploy a variety of surgical tools for different endoscopic operations.
A stent is a resilient device often used in anchoring vascular grafts and for supporting body openings during the grafting of vessels and tubes of the body during surgery. Also, stents are frequently used, without grafts, for supporting luminal patency. More recently, artificial (woven or non woven polymeric) grafts are used in cardiac, vascular, and nonvascular applications to provide extra support. Moreover, stents can be separated into self-expanding and plastically deformed stents. A self-expanding stent is deployed by its self-expanding resilience. A plastically deformed stent is deployed by plastic deformation of the constituent material with a balloon or other such dilating instrument.
Endoscopes are effectively utilized to deploy stents within a body cavity in a minimally invasive manner. In a conventional method, a stent is compressed to fit into the working channel of the endoscope and is delivered to the body cavity to be treated. However, storing a stent within the working channel of an endoscope causes several problems. First, there is a limitation on the size of the stent that can be compressed to fit in the working channel. Because the working channel of the endoscope is often relatively small, a large stent may not fit within the working channel. Thus, this method is not suitable for deploying large stents.
Additionally, fitting a stent in the working channel often results in deformation of the stent when it is deployed into the body cavity. Since stents are made of resilient material, compression within the working channel may cause the stent to become deformed and fail to return to its original shape when released from the working channel. The more the stent gets strained, the more the deformation is likely to be.
A specific example of the aforementioned problems can be seen when observing commonly used methods for positioning and deploying pulmonary stents. Currently, surgeons insert a bronchoscope into an air passageway of a patient to visually observe where a pulmonary stent needs to be positioned. They typically use a type of guide wire inserted through the bronchoscope to mark the position where they want to place the pulmonary stent. At this point, the bronchoscope is removed and a stent delivery system (typically associated with delivering vascular stents) is used to place the pulmonary stent using the guide wire and fluoroscopy or radioscopy to assist in positioning. This current technique requires several distinct and difficult steps and does not allow the surgeon to visually observe the actual placement of the stent. There is a need for a stent delivery system which allows for visual observation during placement of the stent and which requires fewer steps.
Consequently, there is a need for stent deployment systems and methods that provide a solution to the aforementioned problems and permit deployment of stents, regardless of size, into body cavities.